Detection of tumor parenchymal blood flow in hepatic tumors: value of second harmonic imaging with a galactose-based contrast agent

Purpose. To evaluate the detectability of tumor vascularity in hepatic tumo rs by second harmonic imaging with the administration of a microbubble cont rast agent, Levovist. Materials and methods: Twenty-four patients with hepa tic tumors (21 hepatocellular carcinoma,, one focal nodular hyperplasia. an d two liver metastasis) were studied using Aloka SSD 5500 with the administ ration of Levovist. Intermittent harmonic gray-scale imaging (HGSI) and int ermittent harmonic power Doppler imaging (HPDI) were performed on every tum or and the detectability of the two harmonic imaging modes were compared wi th that of dynamic CT. Results: Tumor vessels and tumor parenchymal blood f low were obtained in hypervascular tumors in the early arterial phase, and metastasis presented peripheral enhancement. When dynamic CT was taken as a gold standard, the sensitivity, specificity and accuracy of detecting tumo r vascularity for intermittent HGSI were 55.6, 100 and 66.7%, and for inter mittent HPDI were 83.3, 100 and 87.5%, respectively. The difference of dete ctability between the two modes was statistically significant (P < 0.05). D epth of the lesion from the abdominal wall was a major factor affecting the detectability of tumor vascularity. Conclusion: With the administration of Levovist, intermittent HPDI was more sensitive than intermittent HGSI to d emonstrate tumor vessels and tumor blood flow. Second harmonic imaging with Levovist would be a promising valuable means for investigating specific va scular features in hepatic tumors. (C) 2001 Elsevier Science Ireland Ltd. A ll rights reserved.